U.S. patent application number 13/794319 was filed with the patent office on 2014-09-11 for filter media.
This patent application is currently assigned to Southern Felt Company, Inc.. The applicant listed for this patent is SOUTHERN FELT COMPANY, INC.. Invention is credited to Michael Konesky, William H. Moore, Michael A. Sudduth, Eric W. Winters.
Application Number | 20140250848 13/794319 |
Document ID | / |
Family ID | 51486073 |
Filed Date | 2014-09-11 |
United States Patent
Application |
20140250848 |
Kind Code |
A1 |
Winters; Eric W. ; et
al. |
September 11, 2014 |
Filter Media
Abstract
A nonwoven filter media comprising: polyphenylene sulfide
fibers, an inorganic fibers wherein said filter media exhibits
physical properties taken from the group consisting of: (a) a clean
gas concentration of less than 0.1 mg/m.sup.3, (b) an average cycle
time of greater than 125 seconds when the media at 16.0 ounces per
square yard is tested per ASTM-D6830-02, (c) residual pressure drop
of less than 350 Pa as measured by ASTM-D6830-02; (d) weight of
between 5.0 and 20.0 ounces per yard.sup.2 and a thickness between
0.020 and 0.100 inches, (e) air permeability of between 10 and 60
cubic feet per minute, (f) Mullen Burst strength of 225
lbs/inch.sup.2, (g) less than 50% strength loss according to a
tensile test after being submerged in sulfuric acid according to
test ASTM-D461-93, (h) total mass removal efficiency of 99.99% and
(i) resists burn-through by a stainless steel ball bearings heated
to 800.degree. C.
Inventors: |
Winters; Eric W.; (North
Augusta, SC) ; Konesky; Michael; (Evans, GA) ;
Moore; William H.; (Martinez, GA) ; Sudduth; Michael
A.; (Aiken, SC) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SOUTHERN FELT COMPANY, INC. |
North Augusta |
SC |
US |
|
|
Assignee: |
Southern Felt Company, Inc.
North Augusta
SC
|
Family ID: |
51486073 |
Appl. No.: |
13/794319 |
Filed: |
March 11, 2013 |
Current U.S.
Class: |
55/528 |
Current CPC
Class: |
B01D 2239/1233 20130101;
B01D 39/2017 20130101; B01D 2239/0654 20130101; B01D 39/1623
20130101; B01D 39/2041 20130101 |
Class at
Publication: |
55/528 |
International
Class: |
B01D 39/16 20060101
B01D039/16; B01D 39/20 20060101 B01D039/20 |
Claims
1. A non woven filter media comprising: polyphenylene sulfide
fibers having a denier between 0.5 and 10.0 and present in an
amount between 70% and 80% by weight in said non woven filter
media; inorganic fibers having a denier between 0.5 and 6.0,
present in an amount between 20% and 30% by weight in said non
woven filter media, wherein said inorganic fiber includes at least
90% by weight SiO.sub.2, 4.0% by weight of Al.sub.2O.sub.3; and,
said non woven filter media exhibits a clean gas concentration of
less than 0.1 mg/m.sup.3 and an average cycle time of greater than
125 seconds when the media at 16.0 ounces per square yard is tested
per ASTM-D6830-02.
2. The nonwoven filter media of claim 1 including a scrim
supporting said filter media.
3. The nonwoven filter media of claim 2 wherein said scrim is a 1
to 6 ounce scrim.
4. The nonwoven filter media of claim 1 wherein said filter media
has a weight of between 5.0 and 20.0 ounces per square yard, a
thickness between 0.020 and 0.100 inches, air permeability of
between 10 and 60 cubic feet per minute and Mullen Burst strength
of at least 225 pounds per square inch.
5. The nonwoven filter media of claim 1 wherein said filter media
exhibits less than 50% strength loss according to a tensile test
after being submerged in sulfuric acid of at least a 6%
concentration for 30 minutes according to tensile test
ASTM-D461-93.
6. The nonwoven filter media of claim 1 wherein said filter media
exhibits less than 50% strength loss according to a tensile test
after being submerged in sulfuric acid having a concentration
between 5.0% and 7.0% for between 0 and 30 minutes according to
tensile test ASTM-D461-93.
7. The nonwoven filter media of claim 1 wherein said polyphenylene
sulfide fibers have a length of between 1 and 4 inches and a
diameter of between 7 and 36 microns and said inorganic fibers have
a length of between 1 and 4 inches and a diameter of between 5 and
30 microns.
8. The nonwoven filter media of claim 1 wherein said filter media
exhibits a total mass removal efficiency of about 99.99% according
to ASTM test method D6830-02.
9. The nonwoven filter media of claim 1 wherein said filter media
resists burn-through by a stainless steel ball bearings of between
about 1/4 to 1/2 inches in diameter, heated at least to 800.degree.
C. wherein said heated ball bearing is placed on said filter media
that is stretched horizontally across a frame.
10. The nonwoven filter media of claim 1 wherein said filter media
exhibits a residual pressure drop of less than 350 Pa as measured
by ASTM-D6830-02.
11. A filter media comprising: a first polymer fiber having a
denier between 0.5 and 10.0 and present in an amount between 5% and
95% by weight in said filter media and taken from the group
consisting of: polyphenylene sulfide, polyester, meta-aramid,
para-aramid, acrylic, PTFE, Polyimide, glass, nylon; and inorganic
fibers having a denier between 0.5 and 6.0, present in an amount
between 5% and 95% by weight in said filter media, wherein said
inorganic fiber includes at least 90% by weight SiO.sub.2, 4.0% by
weight of Al.sub.2O.sub.3.
12. The filter media of claim 11 including a scrim supporting said
first polymer fiber and said inorganic fibers.
13. The filter media of claim 11 wherein said filter media includes
physical properties taken from the group consisting of: (a) weight
of between 5.0 and 20.0 ounces per square yard, (b) thickness
between 0.020 and 0.100 inches, (c) air permeability of between 10
and 60 cubic feet per minute and (d) Mullen Burst strength of at
least 225 pounds per square inch.
14. The filter media of claim 11 wherein said filter media exhibits
less than 50% strength loss according to a tensile test after being
submerged in sulfuric acid solution of at least 6% concentration
for at least 30 minutes.
15. The filter media of claim 11 wherein said tensile test is
preformed according to tensile test ASTM-D461-93.
16. A nonwoven filter media comprising: polyphenylene sulfide
fibers present in an amount between 70% and 80% by weight in said
filter media; inorganic fibers present in an amount between 20% and
30% by weight in said filter media and wherein said filter media
exhibits physical properties taken from the group consisting of:
(a) a clean gas concentration of less than 0.1 mg/m.sup.3, (b) an
average cycle time of greater than 125 seconds when the media at
16.0 ounces per square yard is tested per ASTM-D6830-02, (c)
residual pressure drop of less than 350 Pa as measured by
ASTM-D6830-02; (d) weight of between 5.0 and 20.0 ounces per square
yard and a thickness between 0.020 and 0.100 inches, (e) air
permeability of between 10 and 60 cubic feet per minute, (f) Mullen
Burst strength of at least 225 pounds per square inch, (g) less
than 50% strength loss according to a tensile test after being
submerged in sulfuric acid of at least a 6% concentration for at
least 30 minutes according to tensile test ASTM-D461-93, (h) total
mass removal efficiency of about 99.99% according to ASTM test
method D6830-02 and (i) resists burn-through by a stainless steel
ball bearings of between about 1/4 to 1/2 inches in diameter,
heated at least to 800.degree. C. wherein said heated ball bearing
is placed on said filter media that is stretched horizontally
across a frame.
17. The nonwoven filter media of claim 16 wherein said inorganic
fiber includes at least 90% by weight SiO.sub.2, 4.0% by weight of
Al.sub.2O.sub.3.
18. The nonwoven filter media of claim 16 including a scrim
supporting said first fibers and said inorganic fibers.
19. The nonwoven filter media of claim 16 wherein said filter media
for use in operational environments between 80.degree. C. and
200.degree. C.
20. The nonwoven filter media of claim 16 including a first layer
and a second layer of nonwoven filter media supported by a
scrim.
21. The nonwoven filter media of claim 16 that is laminated with a
PTFE membrane.
22. The nonwoven filter media of claim 16 that is chemically
treated.
23. The nonwoven filter media of claim 16 that has two or more
fibers blended with the inorganic fiber.
Description
FIELD OF THE INVENTION
[0001] This invention is directed to a filter media with improved
heat resistance and performance properties, specifically, a filter
media with improved cycle times, particulate removal efficiency,
heat resistance and chemical resistance.
BACKGROUND OF THE INVENTION
[0002] In several industries, baghouses having bag filters are used
to remove dust and other particulates from the an air stream. Some
of the industries that use bag houses to remove particulates from
the air stream include garbage incinerators, coal plants or
boilers, furnaces for melting metal and other materials,
pharmaceutical production food manufacturing, chemical production
and cement plants.
[0003] Most baghouses use long, cylindrical filter bags or tubes
made of fabric as the filter medium. Gas having particles enters
the baghouse through hopper (10 of FIG. 1) which generally is a
large funnel-shaped containers used for collecting and dispensing
the particulate. The gas is then directed through the filter bags
12 in a manifold where the filtered air exits the baghouse.
Particulate in the gas stream are deposited on the filter bag.
Periodically, compressed air or other means is used to reverse the
flow of gas through the bag filter which results in the filter cake
or particulates being forced off the filter bags. The particulate
then drops to the bottom of the hopper and can be removed from the
hopper. The particulates collect on the bag due to at least one of
the following forces: inertial collection, interception, Brownian
movement and electrostatic forces.
[0004] Depending upon the industry and application of the baghouse,
the operating temperature of the baghouse can be in the range of
50.degree. C. to 250.degree. C. Therefore the filter bags need to
be able to function in these operational temperatures. One
significant risk associated with some applications is the risk of
embers, heated particles or sparks being present in the hopper. In
the event that an ember or other hot particle contacts the filter
media, a hole can be burned in the filter media severely hampering
or completely eliminating its effectiveness. A spark can also
create an undesirably opening in the filter bag.
[0005] In some applications, the gas includes particles that are
heated such as in the coal, chemical, metal industries. These
heated particles can contact the filter bag and damage the bag
rendered the filtering functionality ineffective. Further, there
can be chemicals in the air stream that are corrosive or otherwise
damaging to the filter bag itself.
[0006] Therefore, it would be advantageous to have a filter bag for
a baghouse that was resistant to heated particles and corrosive
chemicals while maintaining or improving the performance properties
of traditional filter bags.
SUMMARY OF THE INVENTION
[0007] To further the objectives above, this invention provides for
non woven filter media comprising: polyphenylene sulfide fibers
having a denier between 0.5 and 10.0 and present in an amount
between 70% and 80% by weight in said non woven filter media;
inorganic fibers having a denier between 0.5 and 6.0, present in an
amount between 20% and 30% by weight in said non woven filter
media, wherein said inorganic fiber includes at least 90% by weight
SiO.sub.2, 4.0% by weight of Al.sub.2O.sub.3; and, said non woven
filter media exhibits a clean gas concentration of less than 0.1
mg/m.sup.3 and an average cycle time of greater than 125 seconds
when the media at 16.0 ounces per square yard is tested per
ASTM-D6830-02.
[0008] The invention can also include filter media comprising: a
first polymer fiber having a denier between 2.5 and 3.0 and present
in an amount between 5% and 95% by weight in said filter media and
taken from the group consisting of: polyphenylene sulfide,
polyester, meta-aramid, para-aramid, acrylic, PTFE, Polyimide,
glass, nylon; and, inorganic fibers having a denier between 0.5 and
1.5, present in an amount between 5% and 95% by weight in said
filter media, wherein said inorganic fiber includes at least 90% by
weight SiO.sub.2, 4.0% by weight of Al.sub.2O.sub.3.
[0009] The invention can also include a nonwoven filter media
comprising: polyphenylene sulfide fibers present in an amount
between 70% and 80% by weight in the filter media; inorganic fibers
present in an amount between 20% and 30% by weight in the filter
media and wherein the filter media exhibits physical properties
taken from the group consisting of: (a) a clean gas concentration
of less than 0.1 mg/m.sup.3, (b) an average cycle time of greater
than 125 seconds when the media at 16.0 ounces per square yard is
tested per ASTM-D6830-02, (c) residual pressure drop of less than
350 Pa as measured by ASTM-D6830-02; (d) weight of between 5.0 and
20.0 ounces per square yard and a thickness between 0.020 and 0.100
inches, (e) air permeability of between 10 and 60 cubic feet per
minute, (f) Mullen Burst strength of at least 225 pounds per square
inch, (g) less than 50% strength loss according to a tensile test
after being submerged in sulfuric acid of at least a 6%
concentration for at least 30 minutes according to tensile test
ASTM-D461-93, (h) total mass removal efficiency of about 99.99%
according to ASTM test method D6830-02 and (i) resists burn-through
by a stainless steel ball bearings of between about 1/4 to 1/2
inches in diameter, heated at least to 800.degree. C. wherein the
heated ball bearing is placed on the filter media that is stretched
horizontally across a frame.
DESCRIPTION OF THE DRAWINGS
[0010] The following description is better understood with
reference to the incorporated drawings which are part of the
description of the invention:
[0011] FIG. 1 is a front view of prior art;
[0012] FIG. 2 is a cross section of the invention;
[0013] FIG. 3 is a cross section of the invention; and,
[0014] FIGS. 4A and 4B are test results of the invention.
DETAIL DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENT
[0015] This invention relates to a composition of fibers and filter
media made there from that provide for advantageous physical
properties, especially for use with bag filters for a baghouse. In
one embodiment, the fiber composition that can be used for a filter
media includes a blend of polyphenylene sulfide fibers that are
present in an amount between 70% and 80% in the blended fiber. The
denier of these fibers can be between 0.5 and 10.0 and the fiber
can be non-woven. An inorganic fiber can also be present in an
amount between 20% and 30% by weight. In one embodiment, the
inorganic fiber includes at least 90% by weight of SiO.sub.2 and
4.0% by weight of Al.sub.2O.sub.3. The denier of the inorganic
fiber can be between 0.5 and 6.0. In one embodiment, the
polyphenylene sulfide is present in an amount between 70% and 80%
by weight in the filter media. The inorganic fiber is present in an
amount between 20% and 30% by weight.
[0016] The filter media manufactured from the blended fibers can be
used in operational environments that have temperatures in the
range between 80.degree. C. and 200.degree. C.
[0017] In one embodiment, a first polymer taken from the group of
polyphenylene sulfide, polyester, meta-aramid, para-aramid,
acrylic, PTFE, Polyimide, glass and nylon is present in a filter
media in an amount between 5% and 95% by weight. The first polymer
can have a denier of between 0.5 and 10.0. A second inorganic fiber
is blended with the first polymer and present in an amount between
5% and 95%. The inorganic fiber can include 90% by weight of
SiO.sub.2 and 4% by weight of Al.sub.2O.sub.3. The first polymer
can have a denier between 0.5 and 10.0 and the inorganic fiber can
have a denier between 0.5 and 6.0. A scrim can be included in the
filter media to support the blended fibers.
[0018] When the polyphenylene sulfide fibers and the inorganic
fibers are blended and used to manufacture a filter media for a bag
filter, the resulting filter can have the physical property of
clean gas concentration of less than 0.1 mg/m3. This physical
property can be determined by the Standard VDI 3926 test criteria
(ASTM-D6830-02), with the following parameters: Tank Pressure 5 Bar
(4.93 atm); Dust Concentration 5 g/m.sup.3; A/C ration of 2; Vale
Opening Time 60 seconds; and Temperature of 25.degree. C.
(77.degree. F.). With the above test parameter and tested filter
media, the following results were achieved as shown in Tables 1 and
2:
TABLE-US-00001 TABLE 1 Sample 10.31 g and 546 g/m.sup.2
Conditioning Aging Stabilizing Measuring Measuring 30 cycles 2,500
pulses 10 cycles @ 1,000 @ 1800 Start of pulsing @ every 20 pulsing
@ Pa. 2 Pa, 3 Test 1,000 Pa seconds 1,000 Pa hours hours Mass
Filter Holder + 499.57 500.49 501.08 501.11 501.39 Sample (g) Mass
Grain of Filter (g) 0 1.02 1.51 1.54 1.82 Residual Pressure Drop 43
60 235 238 239 .DELTA.P.sub.res (Pa) Residual Dust Mass (g/m.sup.2)
66.23 98.05 100.00 118.18 Measuring Time t.sub.m (s) 17,360 50,000
3,424 7,310 Number of Complete Cycles 30 2500 10 24 Average Cycle
Time (s) 579 20 342 305 Dust Penetration m.sub.Abs (mg) 8.8 59.3
-0.1 0.3 Clean Gas Concentration 0.987 2.310 -0.057 0.080 C.sub.c
(mg/m.sup.3)
TABLE-US-00002 TABLE 2 Sample 10.24 g and 542 g/m.sup.2
Conditioning Aging Stabilizing Measuring Measuring 30 cycles 2,500
pulses 10 cycles @ 1,000 @ 1800 Start of pulsing @ every 20 pulsing
@ Pa. 2 Pa, 3 Test 1,000 Pa seconds 1,000 Pa hours hours Mass
Filter Holder + 499.51 500.18 501.23 501.20 501.15 Sample (g) Mass
Grain of Filter (g) 0 0.67 1.72 1.69 1.64 Residual Pressure Drop 42
58 242 228 224 .DELTA.P.sub.res (Pa) Residual Dust Mass (g/m.sup.2)
43.51 111.69 109.74 106.49 Measuring Time t.sub.m (s) 18,228 50,000
2,762 7,310 Number of Complete Cycles 30 2500 10 24 Average Cycle
Time (s) 608 20 276 305 Dust Penetration m.sub.Abs (mg) 9.1 99.6
0.3 0.8 Clean Gas Concentration 0.973 3.881 0.212 0.213 C.sub.c
(mg/m.sup.3)
[0019] From these results, we can see that the clean gas
concentration can be less than 0.1 mg/m.sup.3 and the average cycle
time can be greater than 125 seconds. The air permeability can be
between 10 and 60 ft.sup.3/min. The filter media can have a Mullen
Burst strength of at least 225 lbs/inch.sup.2. In one embodiment,
the Mullen Burst strength is between 225 and 245
lbs/inch.sup.2.
[0020] In one embodiment, the filter media manufactured from the
blended fibers has the physical property of total mass removal of
about 99.99% according to test method ASTM D6830-02.
[0021] In one embodiment, the nonwoven filter media can be
supported by a scrim that can be 1.0 to 6.0 ounces in weight. The
weight of the filter media can be between 5.0 and 20.0 ounces per
square yard. The filter media can have a thickness between 0.020
and 0.100 inches.
[0022] In one embodiment, the blended fibers manufactured into a
filter media include the physical property of exhibiting less than
a 50% loss in strength using a tensile test after being submerged
in 6% sulfuric acid for 30 minutes according to test ASTM-D461-93.
In one embodiment, an acid resistance tensile test is preformed
with a testing machine suitable for ASTM D5035-95. A sample of the
blended fabric is cut into about a 2 inch by 6 inch piece in the
machine direction. The specimens are then heated to 400.degree. F.
for 4 hours and then the samples are cooled to ambient temperature.
The samples are placed in a dish with an acid solution of 1N
H.sub.2SO.sub.4 heated to 175.degree. F. for 5 minutes. The samples
are then dried hanging in an oven for 5 minutes at 400.degree. F.
then cooled to ambient temperature. The process of placing the
sample in the 1N H.sub.2SO.sub.4 solution then drying and cooling
the sample defines one cycle. The samples are then tested using
test method ASTM 5035-95 for strength and elongation with a 50-lbs
load. Several of the specimens can be further submerged in 1N
H.sub.2SO.sub.4 heated to 175.degree. F. for an addition 5 minutes
and then dried hanging in an oven for 5 minutes at 400.degree. F.
then cooled to ambient temperature for further testing. Using the
acid resistance tensile test, the results are shown in FIGS. 4A and
4B.
[0023] From the acid resistance tensile test, it can be seen that
after the first two cycles, the sample can withstand over 160 Ids
of force. At break, after the third and fourth cycle, the sample
can withstand 80 Ids of force. After the fifth and sixth cycles,
the sample can withstand about 70 pounds of force. In terms of
percentage strength loss, the sample exhibits virtually no loss
after the first two cycles. The second and third cycle results in
less than 5% strength loss and the fifth and sixth cycle results in
less than 60% loss. The following table illustrates the physical
property benefit of the present invention when compared to a
polyphenylene sulfide (PPS) fiber alone.
TABLE-US-00003 TABLE 3 Pounds Of Percentage Force Strength Loss
Cycle Invention PPS Invention PPS 1 ~165 ~140 0 0 2 ~165 ~135 0 5 3
~85 ~40 47 71 4 ~85 ~38 47 75 5 ~70 ~39 57 75 6 ~70 ~38 57 77
[0024] Using a stainless steel ball bearing having a diameter of
between 1/4 and 1/2 inches and heated to at least 800.degree. C., a
sample of the present invention will support the ball bearing when
it is placed on filter media stretched horizontally across a
frame.
[0025] In one embodiment, the polyphenylene sulfide fibers have a
length of between 1 and 4 inches and a diameter of between 7 and 36
microns and said inorganic fibers have a length of between 1 and 4
inches and a diameter of between 5 and 20 microns.
[0026] Referring to FIGS. 1 and 2, the blended fibers are shown.
The fibers 14 with the larger diameter principally consist of
polyphenylene sulfide and the fibers 16 with the smaller diameters
are the inorganic fibers. The scrim 18 is also shown disposed in
the blend of fibers. The inorganic fibers are blended with the
polyphenylene sulfide fibers and supported by a scrim.
* * * * *